1. Field of the Invention
The present invention pertains to external defibrillators and in particular to the paddle-shaped electrodes employed therewith.
2. Description of the Related Art
Defibrillation has proven to be an effective treatment technique for alleviating certain types of cardiac malfunction, and has oftentimes been proven to be indispensable in critical life-saving situations.
Typically, an external defibrillator system includes an electronics package, a pair of defibrillator electrodes to be placed in contact with the patient's body, and one or more multi-conductor cables coupling the defibrillator electrodes and the electronics package. Typically, because the connecting cables must provide adequate high voltage electrical insulation, the cables employed are relatively bulky, heavy and inflexible. Coiling of the cables alleviates inherent stiffness to some extent, but a considerable effort must be made to manage the cables, especially during times of stress associated with life threatening situations which can be adequately addressed only by the most prompt deployment of the defibrillator equipment. With continuous coiling of the high voltage cables, extra length may be gained by uncoiling, but at times this requires a concentrated effort which must be assiduously monitored to avoid shifting careful orientation of the electrodes with respect to the patient's anatomy.
Because of the nature of the medical emergency being treated, effective monitoring of the patient's condition is oftentimes required for successful treatment. For this reason, cardiac monitoring equipment is oftentimes incorporated with the defibrillator electronics package to provide the operator with a visual indication of vital information concerning the patient's condition. When monitoring and defibrillating a patient, the optimal location of the cardiac monitoring equipment, and hence the defibrillator electronics package, is at or near the patient's head. If the cardiac monitoring equipment were placed at the feet of the patient, for example, the operator would be required to look in two opposite directions, one for addressing the medical data equipment and the other for addressing the patient's anatomy and proper orientation of the defibrillator electrodes. The optimal location allows the operator to monitor both the patient and the medical data display simultaneously, minimizing the operator's head movement and attendant change of focus.
Unfortunately, defibrillator electrodes are designed such that the interconnecting high voltage cable exits the rear of the electrode assemblies, that is, in a direction toward the patient's feet. Proper placement of the defibrillator electrodes requires the high voltage cables exiting the paddles to pass across the electrical electrodes and the hands of an operator grasping the paddles, so as to maintain their proper orientation with respect to the patient's anatomy, and to overcome distracting forces which may be applied to the cable. During this time, the operator is concerned with avoiding the passage of electrical currents to his own body as well as other people in the immediate vicinity of the medical treatment. By their nature, cardiac defibrillators are employed on an emergency basis. Whether the patient is being treated in the field or in a hospital setting, the immediate vicinity of the patient is usually very busy and considerable care must be taken to prevent unintended electrical shock of adjacent bystanders.
As mentioned above, the placement of the high voltage cables is somewhat awkward, and despite care in maintaining equipment, operators will sometimes experience micro or mild electrical shocks. During initial set-up, when first preparing for a defibrillator procedure, effective cardiac treatment time is very brief and operators are under considerable strain to effectively carry out the defibrillator procedure in an optimally efficient manner. At this critical time, an operator is required to compensate for mechanical strains and vibrations in the interconnecting high voltage cables. At times the operator is required to untangle cumbersome coiled high voltage cables, and oftentimes is required to configure the cables so as to loop over one or both hands in order to keep the high voltage cables away from the electrically active circuits of the electrodes, as previously mentioned.
Further, because the cables exit the rear of the electrodes, a longer cable length is required with the undesirable consequence that greater current leakage, greater capacitive coupling and at times compromise of the energy transfer interface results. In order to enhance energy transfer, a defibrillation gel is applied to the electrically active surface of the paddle electrodes. Because of the inherent tendency of the cables to pass across the electrically active surface of the electrodes, the cables tend to come in contact with the defibrillation gel, thus compromising their electrical insulation containing the high voltage pulse being transmitted. At a minimum, the operator's suseptance to micro shocks is heightened by the resulting contamination of the high voltage cables, with the outer surface of the cables being electrically coupled to the operator's body by the contaminating defibrillation gel.